What are the specifications for the mounting screws provided with a Shure phono cartridge?
The mounting screw is specified as:
#3-48 UNC 2A
#3 = the screw diameter. Slightly less than 1/10 of an inch (2.5 mm).
48 = 48 threads per inch
UNC = Unified National Coarse (type of thread)
2 = thread precision (average)
A = external thread (B = internal thread like on a nut)
The length of the mounting screw varies based on the thickness of phono cartridge body. Typical lengths are 1/2 inch (13mm) to 7/8 inch (22 mm). The cartridge body has a slot through which the fastening screw passes: the diameter of this slot is typically 1/8".